Control of stationary cross-flow modes in a Mach 6 boundary layer using patterned roughness

2018 ◽  
Vol 856 ◽  
pp. 822-849 ◽  
Author(s):  
Thomas Corke ◽  
Alexander Arndt ◽  
Eric Matlis ◽  
Michael Semper
Keyword(s):  
Boundary Layer ◽  
Total Pressure ◽  
Flow Instability ◽  
Cone Angle ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Cross Flow ◽  
Fast Response ◽  
Transition Control ◽  
Cone Model

Experiments were performed to investigate passive discrete roughness for transition control on a sharp right-circular cone at an angle of attack at Mach 6.0. A cone angle of attack of $6^{\circ }$ was set to produce a mean cross-flow velocity component in the boundary layer over the cone by which the cross-flow instability was the dominant mechanism of turbulent transition. The approach to transition control is based on exciting less-amplified (subcritical) stationary cross-flow modes through the addition of discrete roughness that suppresses the growth of the more-amplified (critical) cross-flow modes, and thereby delays transition. The passive roughness consisted of indentations (dimples) that were evenly spaced around the cone at an axial location that was just upstream of the first linear stability neutral growth branch for cross-flow modes. The experiments were performed in the air force academy (AFA) Mach 6.0 Ludwieg Tube Facility. The cone model was equipped with a motorized three-dimensional traversing mechanism that mounted on the support sting. The traversing mechanism held a closely spaced pair of fast-response total pressure Pitot probes. The measurements consisted of surface oil flow visualization and off-wall azimuthal profiles of mean and fluctuating total pressure at different axial locations. These documented an 25 % increase in the transition Reynolds number with the subcritical roughness. In addition, the experiments revealed evidence of a nonlinear, sum and difference interaction between stationary and travelling cross-flow modes that might indicate a mechanism of early transition in conventional (noisy) hypersonic wind tunnels.

scholarly journals Transition control in a three-dimensional boundary layer at elevated free stream turbulence using dielectric barrier discharge

2019 ◽  
Vol 486 (6) ◽  
pp. 668-672
Author(s):  
S. A. Baranov ◽  
A. Ph. Kiselev ◽  
I. A. Moralev ◽  
D. S. Sboev ◽  
S. N. Tolkachev ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Dielectric Barrier Discharge ◽  
Free Stream ◽  
Barrier Discharge ◽  
Flow Instability ◽  
Three Dimensional ◽  
Cross Flow ◽  
Dielectric Barrier ◽  
Free Stream Turbulence ◽  
Dimensional Boundary

The results of an experimental study of the effect of dielectric barrier discharge (DBR) actuator on laminar-turbulent transition in a three-dimensional boundary layer under influence of elevated free-stream turbulence are presented. The travelling cross-flow instability modes are dominated in transition in a base configuration. Their characteristics do not depend on a spanwise position. The DBD-actuator that generated stationary cross-flow vortices with the predefined spanwise wavelength when turned on was capable to reduce a turbulent spots production rate in comparison to the base regime.

Attenuation of Cross-Flow Instability in a Three-Dimensional Boundary Layer by Means of a Multidischarge Actuator System

2019 ◽  
Vol 64 (9) ◽  
pp. 365-369
Author(s):  
S. A. Baranov ◽  
M. D. Gamirullin ◽  
A. Ph. Kiselev ◽  
A. P. Kuryachii ◽  
D. S. Sboev ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flow Instability ◽  
Three Dimensional ◽  
Cross Flow ◽  
Dimensional Boundary ◽  
Actuator System

scholarly journals Attenuation of cross-flow instability in three-dimensional boundary layer by means of multi-discharge actuator system

2019 ◽  
Vol 488 (2) ◽  
pp. 147-152
Author(s):  
S. A. Baranov ◽  
M. D. Gamirullin ◽  
A. Ph. Kiselev ◽  
A. P. Kuryachii ◽  
D. S. Sboev ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Body Force ◽  
Flow Instability ◽  
Three Dimensional ◽  
Cross Flow ◽  
The Body ◽  
Subsonic Wind Tunnel ◽  
Significant Area ◽  
Dimensional Boundary ◽  
Force Impact

Results of experiments in low-turbulence subsonic wind tunnel sustaining the possibility of significant attenuation of the cross-flow velocity and the intensity of stationary instability vortices due to the body force impact on three-dimensional boundary layer are presented. The unidirectional body force over a significant area of the streamlined surface has been created with the help of dielectric barrier discharge actuator.

Control of the secondary cross-flow instability using localized suction

2012 ◽  
Vol 706 ◽  
pp. 470-495 ◽  
Author(s):  
Tillmann Friederich ◽  
Markus J. Kloker
Keyword(s):  
Flow Instability ◽  
Three Dimensional ◽  
Cross Flow ◽  
Base Flow ◽  
Transition To Turbulence ◽  
Significant Delay ◽  
Transition Control ◽  
Dimensional Boundary ◽  
Nonlinear Disturbance ◽  
Layer Flow

AbstractTransition control by suction in a three-dimensional boundary-layer flow subject to cross-flow instability is investigated using direct numerical simulation. Whereas the classical application of (homogeneous) suction at the wall is aimed at modifying the quasi-two-dimensional base flow to weaken primary cross-flow instability, here the three-dimensional nonlinear disturbance state with large-amplitude steady cross-flow vortices (CFVs) is controlled. Strong, localized ‘pinpoint’ suction is shown to be suitable for altering the CFVs and the associated flow field such that secondary instability is weakened or even completely suppressed. Thus significant delay of transition to turbulence can be achieved.

Some observations of the transition process on the windward face of a long yawed cylinder

1985 ◽  
Vol 150 ◽  
pp. 329-356 ◽  
Author(s):  
D. I. A. Poll
Keyword(s):  
Boundary Layer ◽  
Flow Instability ◽  
Three Dimensional ◽  
Cross Flow ◽  
Transition Process ◽  
Theoretical Models ◽  
Boundary Layer Flows ◽  
Sufficient Detail ◽  
Oil Flow ◽  
Dimensional Boundary

An experiment has been performed to determine the effect of yaw upon transition in the boundary layer formed on the windward face of a long cylinder. The china-clay-evaporation and surface-oil-flow techniques have been used to study the development of the fixed-wavelength stationary disturbances which are characteristic of cross-flow instability. It has been found that the boundary layer is also susceptible to time-dependent disturbances which grow to very large amplitudes prior to the onset of transition. These disturbances have been studied with a hot-wire anemometer. The conditions necessary for the onset and completion of transition have been determined by the use of surface Pitot tubes. Data from the experiment have been compared with the simple criteria for instability and transition which were proposed by Owen & Randall over thirty years ago. In general it has been found that these criteria are inadequate, and, where possible, improvements have been proposed. The raw data are presented in sufficient detail for them to be used to test, or calibrate, future theoretical models of the transition process in three-dimensional boundary-layer flows.

Effects of Inlet Distortion on the Flow Field in a Transonic Compressor Rotor

1996 ◽  
Author(s):  
Chunill Hah ◽  
Douglas C. Rabe ◽  
Thomas J. Sullivan ◽  
Aspi R. Wadia
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Viscous Flow ◽  
Total Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aerodynamic Loss ◽  
Transonic Compressor ◽  
Inlet Distortion ◽  
Compressor Rotor

The effects of circumferential distortions in inlet total pressure on the flow field in a low-aspect-ratio, high-speed, high-pressure-ratio, transonic compressor rotor are investigated in this paper. The flow field was studied experimentally and numerically with and without inlet total pressure distortion. Total pressure distortion was created by screens mounted upstream from the rotor inlet. Circumferential distortions of 8 periods per revolution were investigated at two different rotor speeds. The unsteady blade surface pressures were measured with miniature pressure transducers mounted in the blade. The flow fields with and without inlet total pressure distortion were analyzed numerically by solving steady and unsteady forms of the Reynolds-averaged Navier-Stokes equations. Steady three-dimensional viscous flow calculations were performed for the flow without inlet distortion while unsteady three-dimensional viscous flow calculations were used for the flow with inlet distortion. For the time-accurate calculation, circumferential and radial variations of the inlet total pressure were used as a time-dependent inflow boundary condition. A second-order implicit scheme was used for the time integration. The experimental measurements and the numerical analysis are highly complementary for this study because of the extreme complexity of the flow field. The current investigation shows that inlet flow distortions travel through the rotor blade passage and are convected into the following stator. At a high rotor speed where the flow is transonic, the passage shock was found to oscillate by as much as 20% of the blade chord, and very strong interactions between the unsteady passage shock and the blade boundary layer were observed. This interaction increases the effective blockage of the passage, resulting in an increased aerodynamic loss and a reduced stall margin. The strong interaction between the passage shock and the blade boundary layer increases the peak aerodynamic loss by about one percent.

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